Chem 103 Exam 3
A cell phone sends signals at about 840 MHz (where 1 MHz = 1 x 10⁶ Hz or cycles per second). What is the wavelength of this radiation?
.35 m
What is the maximum number of electrons that can be identified with the following set of quantum numbers? If there are none, enter 0. n = 3, ℓ = 3
0
What is the rule for l values in an electron?
0 ≤ l < n
Group 1A has __ valence electrons...
1
What is the maximum number of electrons that can be identified with the following set of quantum numbers? If there are none, enter 0. n = 2, ms = -1/2
4
Maximum number of electrons in p orbital?
6
An electron moves with a velocity of 1.2 x 10⁸ cm/s. What is its wavelength?
6.1 x 10⁻¹⁰ m
Plank's Constant
6.6260693x10∧-34J
Compared to 300 nm light, 700 nm light has... A.higher frequency B.lower frequency C.lower energy D.greater intensity
B and C
excited states
H atom with higher energies (n>1)
What is the significance of Zeff?
Is is the attraction felt between the nucleus and valence electrons
Frequency
Refers to the number of waves that pass a given point in some unit of time, usually per second. hertz
Radias ___ across the periodic table and ___ down the periodic table
decrease, increase
Speed of light is ____ proportional to wavelength and frequency. ( c= wavelength x frequency)
directly
What is the Pauli Exclusion Principle significance?
electrons can't occupy the same quantum space at once
What are lone pair electrons?
electrons not involved in bonding
Is the following true or false when explaining the photoelectric effect? The intensity of a light beam is related to its frequency.
false
Ionized energy ___ across the periodic table and ___down the periodic table
increase, increase
As frequency increases, energy...
increases
Electronegativity ___ across the periodic table and ___ down the periodic table
increases, decreases
Electromagnativity ___ across the periodic table and ___ down the periodic table
increases, increases
covalent bonding
involves a sharing of electrons from each atom's outermost shell (valence electrons) between atoms.
quantum number; shape
l
What is electromagnetic radiation also known as?
light
what is the wave nature of electron according to de Broglie's equation?
light is a wave, thus electrons have the same nature. discovered quantum numbers (n-values)
photons
massless particles
magnetic quantum number; orientation
ml
electric spin quantum number
ms
What is the rule for n values in an electron?
n>1
what orbital has a dumb bell shape?
p orbital
What orbital has a spherical shape?
s orbital
diamagnetic
substances in which all electrons are PAIRED experience a slight repulsion when subjected to a magnetic field.
Balmer equation
the -Rhc (1/n2final-1/n2intial) equation
What is an ionic bond?
transfer between a cation to an anion
Is the following true or false when explaining the photoelectric effect? Light can be thought of as consisting of massless particles whose energy is given by Planck's equation, E = hν.
true
Which radiation has the higher frequency, ultraviolet or visible?
ultraviolet
Maximum number of electrons in s orbital?
2
What is the energy of a mole of photons of violet light (450 nm)?
2.7 x 10⁵ J
Group 4A has ___ valence electrons...
4
The ____ of a photon of light is ____ proportional to its frequency and ____ proportional to its wavelength.
Energy, directly, inversely
arrange these elements in increasing radias size: O, Mg, C, Si, Al
O, C, Si, Al, Mg
How do we calculate their frequencies?
Rydberg's equation to E = (c x h)/v
What is photoelectric effects?
certain metals emit electrons when hit with light. light must exceed a threshold of energy before electrons are emitted with kinetic energy.
what orbital has a 4-leafed clover shape?
d orbital
As energy increases, wavelength...
decreases
The light from an amber signal has a wavelength of 595 nm, and that from a green signal has a wavelength of 500 nm. Which has the higher frequency?
green signal
principle quantum number; size
n
What do the l-value letter correspond to in terms of numbers? Answer in s = 4
s = 0, p = 1, d = 2, f = 3
What is the rule for ml values in an electron?
-l ≤ ml ≤ l
What is Planck's equation?
E = wavelength x Plancks constant (6.63x10^-34 J/sec)
How is the line spectra of H atom explained by Rydberg's equation?
The lines we see is energy from electrons moving from an initial state to a final state.
A particular orbital has n = 4 and ℓ = 3. What is the designation for this orbital? Enter an answer such as 1s or 3p.
4f
What are the four quantum numbers related to?
Electron location in an atom. (n, l, ml, ms)
Which light has a higher frequency: blue or red?
Blue
Arrange the elements K, Cs and Rb from smallest to largest atomic radius.
K, Rb, Cs
Maximum number of electrons in d orbital?
10
Maximum number of electrons in f orbital?
14
A neutral atom has two electrons with n = 1, eight electrons with n = 2, and seven electrons with n = 3. What is the atomic number?
17
What is the box orbital configuration of aluminum? Type it like so with periods representing arrows : 1s(..) 2s(..) etc
1s(..) 2s(..) 2p(......) 3s(..) 3p(.)
What is the electron configuration for S2¯?
1s² 2s² 2p⁶ 3s² 3p⁶
According to experiments concerned with the photoelectric effect, which of the following will increase the kinetic energy of an electron ejected from a metal surface? 1.increasing the wavelength of the light striking the surface 2.increasing the frequency of the light striking the surface 3.increasing the number of photons of light striking the surface
2
An energy of 7.0 x 10⁻¹⁹ J/atom is required to cause a copper atom on a metal surface to lose an electron. Calculate the longest possible wavelength of light that can ionize a a copper atom.
2.8 x 10⁻⁷ m
Octet Rule
Basically, it states that every atom wants to have eight valence electrons in its outermost electron shell.
Why do atoms emit light?
Electrons moving to a ground state
Why do atoms absorb light?
Electrons moving to a higher state.
What is the main idea from Bohr's atom structure?
Electrons orbit around the nucleus with only certain number of orbits possible.
What element has the most electronegativity?
Fluorine
Heisenberg's uncertainty principle
If we choose to know the energy of an electron in an atom with only a small uncertainty, then we must accept a corresponding large uncertainty in its position
arrange these elements in order of increasing ionization energy: Ne, N, As, Na
Na, As, N, Ne
What is Einstein's idea of dual nature of light?
That light exists as tiny particles, which he called photons.
What is ionized energy?
The amount of energy required to remove s valence electron to create a cation.
The properties of electromagnetic radiation in terms of frequency, wavelength, and energy
Wavelength is inversely proportional to frequency. Frequency is directly proportional to energy. Energy is inversely proportional to wavelength.
What is the noble gas configuration for titanium?
[Ar] 4s² 3d²
As wavelength increases, frequency...
decreases
What is the Aufbau Principle significance?
electrons fill the lowest available energy levels before filling higher levels
What is Hund's Rule significance?
electrons will fill singularly in an orbital before pairing up
paramagnetic
elements and compounds that have UNPAIRED electrons are attached to a magnetic
Write a complete set of quantum numbers (n, ℓ, and mℓ) that quantum theory allows for the 5p orbital. Answer in n = 2, l = 3, ml = -3, -2, -1, 0, 1, 2, 3
n = 5, l = 1, ml = -1, 0, 1
What is a covalent bond?
shared electrons
What is electron affinity?
the change in energy (in kJ/mole) of an atom when an electron is added to form a negative ion
Wavelength
the distance between a given point on a wave and the corresponding point in the next cycle of the wave Measured as the distance between successive crests or high points of a wave (successive troughs or low points). λ
What are core electrons?
the electrons in the inner orbitals (sometimes represented by a noble gas)
What are valence electrons?
the electrons in the outermost orbital
ionic bond
the electrostatic force of attraction between two oppositely charged ions. The positive ion is called cation, and the negative ion is the anion. It is like the north and south poles of a magnet.
What is electronegativity?
the tendency of an atom to attract a bonding pair of electrons
Which radiation has the longer wavelength, ultraviolet or visible?
visible
